Sound damping wallboard and method of forming a sound damping wallboard

ABSTRACT

A sound damping wallboard and methods of forming a sound damping wallboard are disclosed. The sound damping wallboard comprises a gypsum layer with a gypsum surface having an encasing layer. The encasing layer is partially removed to expose the gypsum surface and form a gypsum surface portion and a first encasing layer portion on the gypsum layer. A sound damping layer is applied to the gypsum layer to cover at least part of the gypsum surface portion and the encasing layer portion.

This application claims the benefit of U.S. Provisional Application No.62/112,547, filed Feb. 5, 2015, which is hereby incorporated byreference in its entirety.

BACKGROUND

A building is typically constructed with walls having a frame comprisingvertically oriented studs connected by horizontally oriented top andbottom plates. The walls often include one or more gypsum wallboardsfastened to the studs and/or plates on each side of the frame or,particularly for exterior walls, one or more gypsum wallboards fastenedto the studs and/or plates on one side of the frame with a non-gypsumbased sheathing attached to an exterior side of the frame. A ceiling ofthe building may also include one or more gypsum wallboards orientedhorizontally and fastened to joists, studs, or other structural membersextending horizontally in the building. Walls and ceilings of thisconstruction often have poor acoustical performance and a low soundtransmission class (STC) rating, which results in noise pollution, lackof privacy, and similar issues in the various spaces of the building.

One method to improve acoustical performance of the walls and ceilingsis to install insulation in the cavities of the walls before attachingwallboards to the wall frame. Other methods include the use ofperpendicular framing and/or rubber sheets, clips, or panels attached tothe frame during wall or ceiling construction. A recent methodincorporates a sound damping adhesive between wallboards to create asingle panel. However, this recent method to improve wall or ceilingacoustical performance requires using a wallboard panel that isdifficult to cut due to the two layers of paper or encasing material inthe middle of the single panel. Further, attempts to couple twowallboards not having paper or encasing material on the inside faces ofthe wallboards have been problematic due to the inability of the sounddamping layer adhesive to bond with the gypsum material of eachwallboard. Such attempts have led to misalignment, warping, and pullingapart of the two wallboards.

Therefore, there exists a need for a sound damping wallboard of a singlepanel structure that is structurally robust with superior STCperformance while requiring minimal effort to cut or score and snap forinstallation.

SUMMARY

A sound damping wallboard is disclosed, that comprises a first gypsumlayer having a first side with a first gypsum surface. A first encasinglayer partially covers the first gypsum surface to form a first encasinglayer portion and a first gypsum surface portion on the first side. Asound damping layer is positioned on the first side, and covers at leastpart of the first encasing layer portion and the first gypsum surfaceportion.

In one embodiment, the sound damping wallboard further comprises asecond gypsum layer having a second side with a second gypsum surface. Asecond encasing layer partially covers the second gypsum surface to forma second encasing layer portion and a second gypsum surface portion onthe second side. The sound damping layer is positioned between the firstand second sides, and covers at least part of the first and secondencasing layer portions and the first and second gypsum surfaceportions.

Methods of forming a sound damping wallboard are also disclosed,comprising the steps of: providing a first gypsum layer having a firstside with a first gypsum surface, and a first encasing layer coveringthe first gypsum surface; removing part of the first encasing layer toexpose the first gypsum surface, and form a first encasing layer portionand a first gypsum surface portion on the first side; and applying asound damping layer to the first side to cover at least part of thefirst encasing layer portion and the first gypsum surface portion.

In an alternative embodiment, the method further comprises the steps of:providing a second gypsum layer having a second side with a secondgypsum surface, and a second encasing layer covering the second gypsumsurface; removing part of the second encasing layer to expose the secondgypsum surface, and form a second encasing layer portion and a secondgypsum surface portion on the second side; and applying a sound dampinglayer between the first side and the second side to cover at least partof the first and second encasing layer portion and the first and secondgypsum surface portion.

BRIEF DESCRIPTION OF THE FIGURES

The embodiments described herein and other features, advantages, anddisclosures contained herein, and the manner of attaining them, will bebetter understood from the following description in conjunction with theaccompanying drawing figures, in which like reference numerals identifylike elements, and wherein:

FIG. 1 illustrates a method of forming a sound damping wallboard inaccordance with aspects of the present disclosure;

FIG. 2 is a perspective view of a gypsum wallboard in accordance withaspects of the present disclosure;

FIG. 3 is an exploded view of a sound damping wallboard formed inaccordance with aspects of the present disclosure;

FIG. 4 illustrates a system for forming a sound damping wallboard inaccordance with further aspects of the present disclosure;

FIG. 5 illustrates a system for forming a sound damping wallboard inaccordance with further aspects of the present disclosure; and

FIG. 6 illustrates a system for forming a sound damping wallboard inaccordance with further aspects of the present disclosure.

DETAILED DESCRIPTION

In the following detailed description of embodiments of the presentdisclosure, reference is made to the accompanying drawings that form apart hereof, and in which is shown by way of illustration, and not byway of limitation, such specific embodiments. It is to be understoodthat other embodiments may be utilized and that changes may be madewithout departing from the spirit and scope of the present disclosure.

Referring now to FIGS. 1-3, a method 10 of forming a sound dampingwallboard 100 and a sound damping wallboard 100 formed by the method 10are provided. The method 10 illustrated in FIG. 1 includes providing, atstep 12, a first gypsum wallboard 119. As shown in FIG. 2, the firstgypsum wallboard 119 includes a gypsum layer or core 115 having a firstside with a first gypsum surface 112 covered by a first encasing layer114. First gypsum wallboard 119 further includes a second side with asecond gypsum surface 116 opposite the first gypsum surface 112, andcovered by a second encasing layer 118. Thus, gypsum layer 115 isdisposed between the first encasing layer 114 and the second encasinglayer 118. The gypsum layer 115 of one or more embodiments is formedfrom a gypsum slurry that is laid onto the second encasing layer 118. Insuch an embodiment, the second encasing layer 118 is referred to as theface encasing layer and the first encasing layer 114 is referred to asthe back encasing layer. In one embodiment, the first encasing layer 114may be wrapped around the gypsum layer 115 to enclose the gypsum layerand form a single panel with encasing layers on both the face and backside and along both long edges 144.

As illustrated in FIG. 1, the method 10 of one or more embodiments ofthe present disclosure further includes providing, at step 14, a secondgypsum wallboard 120. Referring again to FIG. 2, the first gypsumwallboard 119 may be identical to the second gypsum wallboard 120. Inanother embodiment, the first gypsum wallboard 119 and the second gypsumwallboard 120 are identical in all aspects except the thickness of eachpanel. As such, the wallboard depicted in FIG. 2 and described abovewith reference to FIG. 2 is referenced for each of the first gypsumwallboard 119 and the second gypsum wallboard 120 of the presentdisclosure. The second gypsum wallboard 120 includes a gypsum layer 115having a third side with a third gypsum surface 122 covered by a thirdencasing layer 124. Second gypsum wallboard 120 further includes afourth side with a fourth gypsum surface 126 opposite the third gypsumsurface 122, and covered by a fourth encasing layer 128. Thus, gypsumlayer 115 of second gypsum wallboard 120 is disposed between the thirdencasing layer 124 and the fourth encasing layer 128. In one or moreembodiments, the gypsum layer 115 is constructed using traditionalgypsum wallboard manufacturing techniques. The gypsum layer 115 of oneor more embodiments is formed from a gypsum slurry that is laid onto thefourth encasing layer 128. In such an embodiment, the fourth encasinglayer 128 is referred to as the face encasing layer and the thirdencasing layer 124 is referred to as the back encasing layer. In oneembodiment, third encasing layer 124 may be wrapped around the gypsumlayer 115 to enclose the gypsum layer and form a single panel withencasing layers on both the face and back side and along both long edges144.

In one or more embodiments, the gypsum layers 115 of one or both gypsumwallboards 119 and 120 are formed using fiberglass particles and/or havea high density core of at least 1200-1400 lbs/msf and a thicknessbetween ¼ and 5/16 inch. In such embodiments, the gypsum layer 115 hashigh strength and allows structural stability to benefit the wallboards119 and/or 120 during the methods disclosed herein. In one or moreembodiments, a gypsum layer 115 of the present disclosure has athickness between about 0.25″ (about ¼ inches) and about 0.375″ (about ⅜inches), pref 5/16″. As discussed below, one or more of the encasinglayers 114, 118, 124, 128 may be formed with a material or structure tofurther enhance strength. The enhanced strength of the gypsum layer 115and/or encasing layers 114, 118, 124, 128 improves acousticalperformance and prevents structural failure of each wallboard duringencasing layer removal (discussed further below), packaging, shipping,handling, and installation.

Further, one or more embodiments of the present disclosure feature afirst encasing layer 114, second encasing layer 118, third encasinglayer 124, and/or fourth encasing layer 128 made from paper (e.g.,recycled furnish), nonwoven glass mat, nonwoven synthetic fiber mats, orother encasing materials commonly utilized by those with ordinary skillin the art. The encasing layers may further include various wet and/ordry strength additives, antimicrobials, and/or sizing to improvestrength and structural performance, as are known in the art. In anembodiment of the present disclosure, the first encasing layer 114and/or third encasing layer 124 is formed as a thin and/or weak layer,being only as strong as necessary to produce a flat, dimensionallysuitable panel, in order to facilitate cutting, breakage, or tearinglater of the first encasing layer 114 and/or third encasing layer 124after the sound damping wallboard is produced, as will be explained infurther detail below. In one or more embodiments, the first encasinglayer 114 and/or third encasing layer 124 is a paper between about 30and about 60 lbs. basis weight or between about 30 and about 60 lbs. perthousand square feet of surface area. In an embodiment, the firstencasing layer 114 and/or third encasing layer 124 is paper havingapproximately 45 lbs. basis weight.

The method 10 illustrated in FIG. 1 further includes removing, at step16, a portion or part of the first encasing layer 114. Referring to FIG.3, removal of a portion of the first encasing layer 114 partiallyexposes first gypsum surface 112 and provides or creates a first gypsumsurface portion 130 and a first encasing layer portion 132 on the firstside of gypsum layer 115. The first gypsum surface portion 130 and/orthe first encasing layer portion 132 may be formed as a singlecontiguous area, or a plurality of noncontiguous areas. In theembodiment illustrated in FIG. 3, the first gypsum surface portion 130is a single contiguous area and the first encasing layer portion 132 isformed as two noncontiguous areas. The area of first gypsum surfaceportion 130 may also be larger and cover more surface area than the(combined) area of first encasing layer portion 132. Reducing therelative area covered by the encasing layer portion 132 is believed tofacilitate cutting or snapping the sound damping wallboard duringinstallation.

In a preferred embodiment, at least part of the first encasing layerportion 132 is positioned adjacent to one or more edges of first gypsumsurface 112. As shown in the embodiment of FIG. 3, a discernible amountof the first encasing layer 114 remains along the opposite longitudinaledges 144 to form first encasing layer portion 132. In one or moreembodiments, first encasing layer portion 132 is formed as either arandom or as an ordered or regular pattern. In the embodiment shown inFIG. 3, first encasing layer portion 132 is formed as a regular patternon the first side of gypsum layer 115—i.e. as an ordered pattern ofstrips or bands parallel or perpendicular to the long edges of thewallboard. Strips parallel to the long edges of the wallboard assist insealing the long edges, and reduce the need for additional tape or edgebanding. As will be explained further, the one or more first encasinglayer portions 132 increase adhesion or bonding performance of the firstgypsum wallboard 119 to a sound damping adhesive, the sound dampinglayer, or the second gypsum wallboard 120 through an adhesive. Further,the presence of one or more first gypsum surface portions 130 and one ormore first encasing layer portions 132 on the first side of gypsum layer115 prevents warping of the first gypsum wallboard 119.

In accordance with one or more embodiments of the present disclosure,the method 10 further includes removing, at step 18 of FIG. 1, a portionor part of the third encasing layer 124 to partially expose third gypsumsurface 122 and provide a second gypsum surface portion 134 and a thirdencasing layer portion 136 on the third side of gypsum layer 115 (secondgypsum wallboard 120). Similar to gypsum wallboard 119, second gypsumsurface portion 134 and/or third encasing layer portion 136 may beformed as a single contiguous area or a plurality of noncontiguousareas. In the embodiment illustrated in FIG. 3, the second gypsumsurface portion 134 is formed as a single contiguous area and the thirdencasing layer portion 136 is formed as two noncontiguous areas. Thesecond gypsum surface portion 134 may be larger and cover more surfacearea than the (combined) area of the third encasing layer portion 136.

In a preferred embodiment, at least part of the third encasing layerportion 136 is positioned adjacent to one or more edges of third gypsumsurface 122. As shown in the embodiment of FIG. 3, a discernible amountof the third encasing layer 124 remains along the opposite longitudinaledges 144 to form third encasing layer portions 136. In one or moreembodiments, third encasing layer portion 136 is formed as either arandom or as an ordered or regular pattern. In a preferred embodiment,third encasing layer portion 136 is formed with a pattern that is thesame or complementary to the pattern of first encasing layer portion132. As will be explained further, third encasing layer portion 136increases adhesion or bonding performance of the second gypsum wallboard120 to a sound damping adhesive, the sound damping layer, or the firstgypsum wallboard 119 through an adhesive. Further, the presence ofsecond gypsum surface portion 134 and third encasing layer portion 136on the third side of gypsum layer 115 prevents warping of the secondgypsum wallboard 120.

Referring now to FIG. 4, an embodiment of the present disclosureincludes removing a portion or part of the first encasing layer 114 byabrasion. A conveyor, belt, or other transporter 152 moves the firstgypsum wallboard 119 toward an abrasive member 150. In an embodiment,the abrasive member 150 includes a rotating or moving surface 153 thatmoves relative to the first gypsum surface 112 of the first gypsumwallboard 119. In one or more embodiments, the surface 153 includes sandor another abrasive material to enable removal of one or more portionsof the first encasing layer 114. In an embodiment, the method 10 furtherincludes cleaning at least one of the first gypsum surface portion 130and the first encasing layer portion 132. As shown in the embodiment ofFIG. 4, one or more vacuum members 154 may be disposed adjacent theabrasive member 150. Further, one or more cleaning vacuum members 156may also be provided to remove dust, debris, and other matter from thesurrounding area and surfaces of the first gypsum wallboard 119.

In an embodiment, the features of the present disclosure illustrated inFIG. 4 are further applied to the second gypsum wallboard 120 withregard to removal of the third encasing layer 124 and cleaning thesurrounding area and surfaces.

Referring now to FIG. 5, an alternative embodiment of the presentdisclosure includes removing the portion of the first encasing layer 114with a planer 160. A conveyor, belt, or other transporter 152 moves thefirst gypsum wallboard 119 toward the planer 160. In an embodiment, theplaner 160 includes a rotating or moving cutting edge(s) 162 that movesrelative to the first side surface 112 of the first gypsum wallboard119. In one or more embodiments, the planer 160 includes a bladed,slotted, or other type of planer 160 to enable removal of one or moreportions of the first encasing layer 114. The planer 160 of one or moreembodiments may include single or multiple blades. In an embodiment, themethod 10 further includes cleaning at least one of the first gypsumsurface portion 130 and the first encasing layer portion 132. As shownin the embodiment of FIG. 5, one or more vacuum members 154 may bedisposed adjacent the planer 160. Further, one or more cleaning vacuummembers 156 may also be provided to remove dust, debris, and othermatter from the surrounding area and surfaces of the first gypsumwallboard 119.

In an embodiment, the features of the present disclosure illustrated inFIG. 5 are further applied to the second gypsum wallboard 120 withregard to removal of the third encasing layer 124 and cleaning thesurrounding area and surfaces.

Referring now to FIG. 6, a further alternative embodiment of the presentdisclosure includes removing the portion of the first encasing layer 114by peeling or pulling a portion of the first encasing layer 114 awayfrom the first gypsum surface 112 with a pulling member 170. A conveyor,belt, or other transporter 152 moves the first gypsum wallboard 119toward the pulling member 170. In an embodiment, the pulling member 170includes a grabbing mechanism or device 172 to engage and retain aleading edge of one or more portions of the first encasing layer 114 asthe first gypsum wallboard 119 moves across the pulling member 170. Asthe first gypsum wallboard 119 moves, the pulling member 170 peels oneor more portions of the first encasing layer 114 away from first gypsumsurface 112 to enable removal of one or more portions of the firstencasing layer 114. In an embodiment, the method 10 further includescleaning at least one of the first gypsum surface portion 130 and thefirst encasing layer portion 132. As shown in the embodiment of FIG. 6,one or more vacuum members 154 may be disposed adjacent the pullingmember 170. Further, one or more cleaning vacuum members 156 may beprovided to remove dust, debris, and other matter from the surroundingarea and surfaces of the first gypsum wallboard 119.

In an embodiment, the features of the present disclosure illustrated inFIG. 6 are further applied to the second gypsum wallboard 120 withregard to removal of the third encasing layer 124 and cleaning thesurrounding areas and surfaces.

Referring again to FIGS. 1-3, the method 10 further includes applying,at step 20, a sound damping layer 140 to the first side of gypsum layer115, to cover first gypsum surface portion 130 and the first encasinglayer portion 132. In one or more embodiments of the present invention,the sound damping layer 140 is a sound damping adhesive. The sounddamping layer 140 of one or more embodiments is a viscoelastic polymerwith a broad Tg range. The sound damping layer 140 of one or moreembodiments includes one or more acrylic polymers and copolymers. Thesound damping layer 140 of one or more embodiments includes a sounddamping layer with sufficient sound damping and adhesive properties tobond the sound damping layer 140 to the first gypsum wallboard 119 andthe second gypsum wallboard 120 while improving the STC performance ofthe previously described framed construction. One of ordinary skill inthe art will recognize the various sound damping materials with adhesiveproperties utilized in the art of sound damping panels that form thesound damping layer 140 of the present disclosure. As shown in FIG. 3,the sound damping layer 140 is applied to the first side of gypsum layer115, to cover at least part of the first gypsum surface portion 130 andthe first encasing layer portion 132. The sound damping layer 140provides enhanced sound damping performance and sufficiently adheres tothe first encasing layer portion 132 to provide enhanced bonding anddimensional stability.

In one embodiment, the sound damping layer 140 is applied between thefirst side of gypsum wallboard 119 and the third side of gypsumwallboard 120 to form a sound damping wallboard 100. The method furtherincludes positioning, at step 22, the third side of gypsum layer 115 ofthe second gypsum wallboard 120 to the sound damping layer 140, tocouple the first gypsum wallboard 119 to the second gypsum wallboard120. As shown in FIG. 3, the sound damping layer 140 covers at leastpart of the second gypsum surface portion 134 and third encasing layerportion 136. The sound damping layer 140 provides enhanced sound dampingperformance and sufficiently adheres to the first and third encasinglayer portions 132 and 136 to provide enhanced bonding and dimensionalstability. In an embodiment, the sound damping layer 140 is positionedon the first side of gypsum wallboard 119 and/or the third side ofgypsum wallboard 120 as a monolithic, homogenous layer. In a furtherembodiment, the sound damping layer 140 covers substantially the entiresurface of the first side of gypsum wallboard 119 and/or the third sideof gypsum wallboard 120, such as shown in FIG. 3.

In one embodiment, the patterns of first and third encasing layerportions 132, 136 are overlapping, such that at least a part of sounddamping layer 140 is positioned between first encasing layer portion 132and third encasing layer portion 136. In a preferred embodiment, firstand third encasing layer portions 132, 136 are formed with the samepatterns that are aligned with each other when the first and secondgypsum wallboards 119, 120 are coupled by the sound damping layer 140 toform sound damping wallboard 100.

In one or more embodiments, the sound damping wallboard 100 may furthercomprise one or more outer encasing layers (not shown) encasing thecomposite structure formed by gypsum wallboards 119 and 120 and sounddamping material 140, to form a single panel structure and furtherimprove strength of the wallboard 100 for packaging, shipping, handling,and/or installation.

The sound damping wallboard 100 of one or more embodiments has athickness between about 0.5″ and about 0.75″. In a preferred embodiment,the sound damping wallboard 100 has a thickness between about ½ inchesand about ⅝ inches, to facilitate use of the sound damping wallboard inthe same applications as conventional wallboard panels. Without asubstantial amount of encasing material at inner layers, the sounddamping wallboard 100 is more easily scored, snapped, and/or cut withoutsacrificing acoustical performance or strength for packaging, shipping,handling, and installation.

As used in the present disclosure, the term “wallboard,” especially withregard to the first gypsum wallboard 119, the second gypsum wallboard120, and the sound damping wallboard 100, generally refers to any panel,sheet, or planar structure, either uniform or formed by connectedportions or pieces. The sound damping wallboard 100 shown in theembodiment of FIG. 3 may form part of a vertical building wall or ahorizontal building ceiling. Multiple sound damping wallboards 100 maybe connected via one or more studs of a wall frame to form a buildingwall structure. One of ordinary skill will recognize the various methodsand structures for fastening, adhering, or otherwise attaching orconstructing the components of a wall or ceiling, including studs,plates, panels, wallboards, etc., to form a building wall or ceiling,and such methods and structures are included in the present disclosure.

We claim:
 1. A sound damping wallboard, comprising: a gypsum layerhaving a first side with a first gypsum surface; a first encasing layerpartially covering the first gypsum surface to form a first encasinglayer portion and a first gypsum surface portion on the first side; anda sound damping layer on the first side, and covering at least part ofthe first encasing layer portion and the first gypsum surface portion.2. The sound damping wallboard of claim 1, wherein the first encasinglayer portion is formed in a regular pattern.
 3. The sound dampingwallboard of claim 1, wherein the first encasing layer portion is formedin a pattern comprising a plurality of parallel bands.
 4. The sounddamping wallboard of claim 1, wherein the first gypsum surface has anedge, and at least part of the first encasing layer portion ispositioned adjacent to the edge.
 5. The sound damping wallboard of claim1, wherein the first gypsum surface has first and second edges oppositeeach other, and at least part of the first encasing layer portion ispositioned adjacent to the first and second edges.
 6. The sound dampingwallboard of claim 1, wherein the sound damping layer comprises aviscoelastic polymer.
 7. The sound damping wallboard of claim 1, furthercomprising: a second gypsum layer having a second side with a secondgypsum surface; a second encasing layer partially covering the secondgypsum surface to form a second encasing layer portion and a secondgypsum surface portion on the second side; and wherein the sound dampinglayer is positioned between the first and second sides, and covers atleast part of the first and second encasing layer portions and the firstand second gypsum surface portions.
 8. The sound damping wallboard ofclaim 7, wherein the sound damping layer comprises a viscoelasticpolymer adhesive.
 9. The sound damping wallboard of claim 7, wherein thefirst and second encasing layer portions are formed in the same pattern.10. The sound damping wallboard of claim 7, wherein at least part of thesound damping layer is positioned between the first and second encasinglayer portions.
 11. A method of forming a sound damping wallboard,comprising the steps of: providing a first gypsum layer having a firstside with a first gypsum surface, and a first encasing layer coveringthe first gypsum surface; removing part of the first encasing layer toexpose the first gypsum surface, and form a first encasing layer portionand a first gypsum surface portion on the first side; applying a sounddamping layer to the first side to cover at least part of the firstencasing layer portion and the first gypsum surface portion.
 12. Themethod of claim 11, wherein the first gypsum surface has an edge, and atleast part of the first encasing layer portion is positioned adjacent tothe edge.
 13. The method of claim 11, wherein the first gypsum surfacehas first and second edges opposite each other, and at least part of thefirst encasing layer portion is positioned adjacent to the first andsecond edges.
 14. The method of claim 11, wherein the first encasinglayer portion is formed in a regular pattern.
 15. The method of claim11, wherein the first encasing layer portion is formed in a patterncomprising a plurality of parallel bands.
 16. The method of claim 11,wherein the sound damping layer is a viscoelastic polymer.
 17. Themethod of claim 11, wherein part of the first encasing layer is removedby abrasion.
 18. The method of claim 11, wherein part of the firstencasing layer is removed by planing.
 19. The method of claim 11,wherein part of the first encasing layer is removed by peeling.
 20. Themethod of claim 11, further comprising the step of cleaning the firstencasing layer portion and the first gypsum surface portion beforeapplying the sound damping layer to the first side.
 21. The method ofclaim 20, wherein the first encasing layer portion and the first gypsumsurface portion are cleaned by a vacuum.
 22. A method of forming a sounddamping wallboard, comprising the steps of: providing a first gypsumlayer having a first side with a first gypsum surface, and a firstencasing layer covering the first gypsum surface; removing part of thefirst encasing layer to expose the first gypsum surface, and form afirst encasing layer portion and a first gypsum surface portion on thefirst side; providing a second gypsum layer having a second side with asecond gypsum surface, and a second encasing layer covering the secondgypsum surface; removing part of the second encasing layer to expose thesecond gypsum surface, and form a second encasing layer portion and asecond gypsum surface portion on the second side; applying a sounddamping layer between the first side and the second side to cover atleast part of the first and second encasing layer portion and the firstand second gypsum surface portion.
 23. The method of claim 22, whereinthe sound damping layer is a viscoelastic polymer adhesive.
 24. Themethod of claim 22, wherein the first and second encasing layer portionsare formed in the same pattern.
 25. The method of claim 22, furthercomprising the step of applying a third encasing layer to encase thestructure formed by the first and second gypsum layers and the sounddamping layer.